Pumping stations in sewage collection systems, also called lift stations, are normally designed to handle raw sewage that is collected and fed from underground gravity pipelines. Sewage is fed into and stored in an underground pit, commonly known as a wet well. The well is equipped with electrical instrumentation to detect the level of sewage present. When the sewage level rises to a predetermined point, a large pump (or pumps) begins to operate to lift the sewage upward through a pressurized pipe system called a sewer force main or rising main from where the sewage is discharged into a gravity manhole. From here the cycle starts all over again until the sewage reaches its point of destination—usually a sewage treatment plant. By this method, pumping stations are used to move waste when necessary to higher elevations.
The criticality of the proper operability of these large sewage pumps cannot be overstated. If a pump should become inoperable due to clogging by sewage debris, for example, a backup in the sewer system can occur, leading to a sanitary sewer overflow—i.e., the discharge of raw sewage into the environment. This scenario occurs too frequently, leaving those in the field looking for an effective means to prevent such discharge.
The sewage pumps most commonly used are end-suction centrifugal pumps with “non-clog” impellers. A “non-clog” impeller is designed to pass a specific sized sphere, for example a three-inch diameter sphere. While these pumps are specially designed with a large open passage so as to avoid clogging with debris or the winding stringy debris onto the impeller, such clogging nevertheless occurs. When the clogging does occur, the pump may bind causing an overload at the pump power source. This could trip the power off, which may further complicate the potential pump problem.
These and other problems are addressed by the present system, devices and methods. Where others have failed to appreciate the problem or have overlooked the solution, the present system provides numerous advantages in operation and effectiveness.